Electric switch



April 1939- 1 I R. F. SAMBLESONI 2,155,244

I ELECTRIC SWITCH Filed Nov. 15, 19:55

' Ihvenfior: I

' Robert E Sambleson,

. *His ttorney.

Patented Apr. 18, 1939 UNITED sTATEs ELECTRIC SWITCH Robert F. Sambleson, Bridgeport, Conn, assignor to General Electric Company, a corporation of New'York Application November 15, 1935, Serial No. 49,931

, 4 Claims.

The present invention relates to electric switches of the type having liquid contact circuitclosers for controlling the flow of current.

The object of my invention is to provide an improved construction and arrangement in a switch of this type, and for a consideration of what I believe to be novel and my invention attention is directed to the accompanying description and the claims appended thereto.

'10 In the accompanying drawing, Fig. l is a sectional side elevation of, a switch embodying my invention; Fig. 2 is a sectional view taken on line 22 of Fig. 1; and Fig. 3 is a diagrammatic view showing the construction and operation of the liquid contact circuit closer.

Referring to the drawing, I have illustrated my invention using a. liquid contact circuit closer having a pair of cup-shaped metal terminals I which are separated by an insulating diaphragm 2 of refractory material, such as a ceramic material. The edges of the terminals are sealed by a head 3 of glass which also seals the junctions between the diaphragm and the terminals. Within the space enclosed by the terminals is a suitable quantity of mercury 4 which forms the conduction medium between the terminals. In the manufacture of the circuit closer, the space enclosed by the terminals is evacuated and filled with hydrogen at a pressure of one or more atmospheres which increases the current interrupting capacity of the circuit closer. As shown by the full lines in Fig. 3, the diaphragm 2 is provided with an opening 5 which is submerged in the mercury when the circuit closer is in the current conductmg position. When the circuit closer is in the current interrupting position, shown in dotted lines in Fig. 3, the opening 5 is above the mercury, and the circuit between the terminals is therefore broken or interrupted by the insulating diaphragm '2. Due to the construction of the circuit closer, the interruption of the circuit between the'terminals takes place in the mercury as the circuit closer is turned so that the opening 5 in the diaphragm approaches the dotted line position. The above described construction is 11- lustrative of a type of liquid contact circuit closer which is suitable for use in a switch embodyingmy invention.

For operating the liquid contact circuit closer, 50 I have provided a handle 6 of moldedthermoplastic material having forked ends I which envelope more than half the periphery of-the circuit closer. One of the forked ends I is provided with projections 8 on opposite sides which fit 5 within recesses e in the terminals of the circuit by the resilience of the forked ends. The grip- 5 ping of the handle is increased by the shrinking of the material of the handle upon cooling so that after the handle has cooled, the circuit closer is tightly ri ed. by the handle. As shown in Fig. 2, the handle is shaped to conform with the outer 10 surface of the circuit closer and is provided with a groove Illwhich fits over the bead 3 and prevents sidewise displacement of the handle relative tothe circuit closer.

The circuit closer is mounted within a housing 15 I l of molded insulating material having side walls l2 in which are molded tubular inserts l3. 0n the inner ends of these inserts are fixed contacts it having a plurality of flexible contact arms i5. In the outer end of the inserts are threaded 2o binding screws I6 which clamp the line conductors to the inserts. The circuit closer is assembled in the housing by sliding between the contacts H. In this position the flexible contact fingers i5 frictionally engage the outer surface of the ter- 25 minals i and conduct electricity to the'terminals. Since a plurality of spring contact fingers l5 are provided, the contact fingers align themselves with the surfaces of the terminals and provide good electrical contact. It is also appar- 80 ent that this construction permits rotation of the liquid contact switch about its axis. The wiping action between the terminals and the contacts tends to prevent increased contact resistance.

At the bottom of the housing is a spring strip 35 the housing. The projections l8 provide sup- 40 ports for the circuitcloser and are also adapted to engage a notch 2| formed in the periphery of the glass bead 3, and thereby to hold the circuit closer resiliently in a fixed position. The circuit closer is held within the housing II and against the projections I8 by two curved spring strips 22 which engage the curved surfaces 23 of the handle on either side of the handle. As shown in Fig. 2, the edges of the spring strips 22' engage the sides of the handle 6 and assist in centering the handle in the housing. The spring strips 22 are riveted to a support or mounting strap 24 which is secured to the top of the housing II by screws 25 threaded into inserts 26 The mounting strap is adapted to be secured to an outlet bqx to mount the switch therein.

In the assembly of the switch, the handle is secured to the liquid contact circuit closer and the contacts I! are secured to the inner end of the inserts l3 in the side walls of the housing. The ends IQ of the spring strip II are then placed in the slots!!! in the bottom wall of the housing, and the circuit closer is inserted in the housing so that the bottom of the glass bead 3 engages the projections ll! of the spring strip l1 and the terminals I engage the contacts l4. The mounting strap 24 is then secured to the top of the housing by the screws 25, thereby holding the circuit closer in place.

In the use of the switch, the switch is mounted in an outlet box by means of the mounting strap 24. Due to the location of the opening 5 in the diaphragm 2, the right-hand end of the mounting strap 24 should be at the top of the outlet box. When so mounted, vertical movement of the handle 6 causes the circuit closer to be rotated about its axis. When the handle is in the raised position, shown in full lines on Fig. 3, the opening 5 in the diaphragm 2 is submerged in the mercury, and an electric circuit is completed through the mercury between the terminals I. When the handle is in the lowered position, as shown in dotted lines in Fig. 3, the opening 5 is raised out of the mercury, and the circuit between the terminals I is broken. The handle is resiliently held in either the raised or the lowered positions by the engagement of one of the projections l8 with the notch 2| in the bead 3. It is apparent that by changing the location of the opening 5 in the diaphragm 2, or by changing the positions of the notches 9 and 21 the switch can be adapted for mounting in other than vertical positions.

What I claim as new and desire to secure'by Letters Patent of the United States is:

1. In an electric switch, a cylindrical liquid contact circuit closer, and a molded handle having forked'ends of thermoplastic material partially enveloping the periphery of the circuit closer, said forked ends being resilient and the surfaces thereof engaging the circuit closer being normally, spaced apart a'less distance than the engaged surfaces on the circuit closer whereby the forked ends are forced apart by the circuit closer and the circuit closer is gripped therebetween and the handle is held thereon by the resilience of said forked ends.

2. In an electric switch, a cylindrical liquid contact circuit closer, and a molded handle having vforked ends of thermoplastic material partially enveloping the periphery of the circuit 3. In an electric switch, a cylindrical liquid contact circuit closer having cup-shaped terminals joined by a bead of sealing material, and a molded handle of thermoplastic material having a groove into which said bead fits and having forked ends partially enveloping the periphery of the terminals and in gripping relation thereto, said handle being held thereon by the resilience of said forked ends, and said circuit closer and one of the forked ends of the handle having interfltting projections and depressions.

4. In an electric switch, 'a cylindrical liquid contact circuit closer having cup-shaped terminals joined by a bead of sealing material, and a molded handle of thermoplastic material having a groove into which said bead fits and having forked ends partially enveloping the periphery of the terminals, said forked ends being resilient and the surfaces thereof engaging the circuit closer being normally spaced apart a less distance than the engaged surfaces on the circuit closer whereby the forked ends are forced apart by the circuit closer and the circuit closer is gripped therebetween and the handle is held thereon by the resilience of said forked end's.

ROBERT F. SALBLESON. 

